also: とっちゃん
noun
Familiar, affectionate term for one's father, used mainly by children or within the family. Similar to お父さん but more casual and intimate.
父ちゃん、今日は何時に帰ってくるの？
Dad, what time are you coming home today?
My dad always lounges around on his days off.
More standard and polite term for father, used by both children and adults. 父ちゃん is more casual and childlike.
Humble term used when referring to one's own father in formal situations or to outsiders. 父ちゃん is informal and affectionate.
Loanword from English, also casual and affectionate, but 父ちゃん has a more traditional Japanese feel.
Derived from 父 (ちち, father) with the affectionate suffix ちゃん, and a sound change from ち to と. The reading とっちゃん is a further contraction.